CVE-2022-49441

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

tty: fix deadlock caused by calling printk() under tty_port->lock

pty_write() invokes kmalloc() which may invoke a normal printk() to print

failure message. This can cause a deadlock in the scenario reported by

syz-bot below:

CPU0 CPU1 CPU2

---- ---- ----

lock(console_owner);

lock(&port_lock_key);

lock(&port->lock);

lock(&port_lock_key);

lock(&port->lock);

lock(console_owner);

As commit dbdda842fe96 ("printk: Add console owner and waiter logic to

load balance console writes") said, such deadlock can be prevented by

using printk_deferred() in kmalloc() (which is invoked in the section

guarded by the port->lock). But there are too many printk() on the

kmalloc() path, and kmalloc() can be c

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References